Abstract: Three casting temperatures(690, 700, 710℃), three mold temperatures(150, 200, 250℃)and three mold filling speeds (1, 2, 3 m/s)were selected.Through L₉ (3³)orthogonal test, different die casting parameters of AlSi9Cu aluminum alloy were designed.Through the analysis of the gas content of 9 groups of parts after actual production, the order of influence of different factors and levels on the die casting experiment in orthogonal test and the optimal process parameters under this design were obtained.The results show that in different parameter ranges, the filling speed has the greatest influence on the final result, and the order of influence is filling speed> pouring temperature> die preheating temperature.According to the gas content, the optimal combination is pouring temperature of 700℃, the filling speed of 2 m/s, and the die preheating temperature of 250℃.Nine groups of AlSi9Cu parts for automobiles with different parameters in the orthogonal test were actually produced and X-ray nondestructive testing was carried out.The test results are basically consistent with the analysis results of the orthogonal test.Using the optimal combination, dense AlSi9Cu parts for automobiles can be produced.